Negative pressure wound therapy is a therapeutic technique used to promote healing and closure of various types of acute or chronic wounds in the human body. Negative pressure wound therapy is a wound bed management technique that creates an environment of sub-atmospheric pressure over the wound bed to draw fluid out of the wound. The effect of the sub-atmospheric pressure environment is to reduce inflammation and increase blood flow within the wound, providing a more oxygen rich environment to the wound and improve the delivery of wound-healing white blood cells, proteins, carbohydrates, and growth factors.
Generally, the wound is irrigated with saline and/or antibiotics, and may be covered with a non-adherent material that adapts to the contours of the wound. An absorptive dressing is applied over the non-adherent material and an occlusive material is applied over the dressed wound to form an air-tight seal. A vacuum tube is connected to an opening in the occlusive material. A vacuum pump applied to the vacuum tube provides the negative pressure needed to draw fluid through the wound for collection and removal. The non-adherent material and/or the absorptive dressing may be changed according to various factors such as the amount of fluid output from the wound, the patient's age, clinical objectives, and the like.
The absorptive dressing may include any one of a number of materials that are chosen as a function of the type of wound, clinical objectives, and the comfort of the patient. For example, the absorptive dressing may include cotton gauze for shallow wounds such as pressure sores or diabetic ulcers of the skin. The absorptive dressing may include a foam material for open cavity wounds such as gunshot wounds, leg ulcers, and surgically created cavities. These wounds may be lightly, moderately, or heavily exuding wounds that may benefit from the high absorption capacity of foam material. The foam material may be cut to fit the margins of the open cavity wound and placed inside the wound. Conventional foam materials generally have pore diameters in the range of approximately 100 μm-600 μm and are consistently used with a protective layer, typically petrolatum gauze, between the foam material and the wound bed in wounds involving fistulas, tendons, nerves or sensitive tissues.